When we got the invitation for a friend's roller skating birthday party I thought for sure we'd end the day at the emergency room. Fortunately that didn't happen for Louie or Benny, or any of the others invited!
Not surprising was the fact that Louie enjoyed playing the games at the rink more than skating; or, that Benny fell a couple of times, but really had a great time on wheels. It sounds like the party was split, on those who were comfortable on skates and those who weren't. I did not share my reservations with the boys because I wanted them to have a good time, but I was always terrified at skating parties. Put me on a court, field, whatever, and I'm fine. But put me on skates or skis and it's over. And from what I know about Kevin, he feels the same way!
As I've gotten older I've learned that it's great to try new things, but not to be discouraged if the new things just aren't for you. Regardless, it sounds like all the kids had a great time.